雅思閱讀模擬試題精選1.Washing，brushingandvarnishingfossils—allstandardconservationtreatmentsusedbymanyfossilhuntersandmuseumcuratorsalike—vastlyreducesthechancesofrecoveringancientDNA.2.Instead，excavatorsshouldbehandlingatleastsomeoftheirbountywithgloves，andfreezingsamplesastheyarefound，dirtandall，concludesapaperintheProceedingsoftheNationalAcademyofSciencestoday.3.AlthoughmanypalaeontologistsknowanecdotallythatthisisthebestwaytouptheoddsofextractinggoodDNA，Eva-MariaGeigloftheJacquesMonodInstituteinParis，France，andhercolleagueshavenowshownjusthowimportantconservationpracticescanbe.Thisinformation，theysay，needstobehammeredhomeamongthepeoplewhoareactuallyoutinthefielddiggingupbones.4.Geiglandhercolleagueslookedat3，200-year-oldfossilbonesbelongingtoasingleindividualofanextinctcattlespecies，calledanaurochs.ThefossilsweredugupatasiteinFranceattwodifferenttimes—eitherin1947，andstoredinamuseumcollection，orin，andconservedinsterileconditionsat-20oC.5.Theteam'sattemptstoextractDNAfromthe1947bonesallfailed.Thenewlyexcavatedfossils，however，allyieldedDNA.6.Becausetheboneshadbeenburiedforthesameamountoftime，andinthesameconditions，theconservationmethodhadtobetoblamesaysGeigl."AsmuchDNAwasdegradedinthese57yearsasinthe3，200yearsbefore，"shesays.Washin，washout7.Becausemanypalaeontologistsbasetheirworkontheshapeoffossilsalone，theirmethodsofconservationarenotdesignedtopreserveDNA，Geiglexplains.8.Thebiggestproblemishowtheyarecleaned.Fossilsareoftenwashedtogetheron-siteinalargebath，whichcanallowwater—andcontaminantsintheformofcontemporaryDNA—topermeateintotheporousbones."NotonlyistheauthenticDNAgettingwashedout，butcontaminationisgettingwashedin，"saysGeigl.9.MostancientDNAspecialistsknowthisalready，saysHendrikPoinar，anevolutionarygeneticistatMcMasterUniversityinOntario，Canada.Butthatdoesn'tmeanthatbestpracticehasbecomewidespreadamongthosewhoactuallyfindthefossils.10.GettingholdoffossilsthathavebeenpreservedwiththeirDNAinmindreliesoncloserelationshipsbetweenlab-basedgeneticistsandtheexcavators，sayspalaeogeneticistSvanteP??booftheMaxPlanckInstituteforEvolutionaryAnthropologyinLeipzig，Germany.Andthatonlyoccursinexceptionalcases，hesays.11.P??bo'steam，whichhasbeensequencingNeanderthalDNA，continuallyfacestheseproblems."WhenyouwanttostudyancienthumanandNeanderthalremains，there'sabigissueofcontaminationwithcontemporaryhumanDNA，"hesays.12.Thisdoesn'tmeanthatallmuseumspecimensarefatallyflawed，notesP??bo.TheNeanderthalfossilsthatwererecentlysequencedinhisownlab，forexample，hadbeenpartofamuseumcollectiontreatedinthetraditionalway.ButP??boiskeentoseesamplesoffossilsfromeverymajorfindpreservedinlinewithGeigl'srecommendations—justincase.Warmandwet14.Muchhumanculturaldevelopmenttookplaceintemperateregions.DNAdoesnotsurvivewellinwarmenvironmentsinthefirstplace，andcanvanishwhenfossilsarewashedandtreated.Forthisreason，Geiglsays，mostancientDNAstudieshavebeendoneonpermafrostsamples，suchasthewoollymammoth，oronremainsshelteredfromtheelementsincoldcaves—includingcavebearandNeanderthalfossils.15.Betterconservationmethods，andafocusonfreshfossils，couldboostDNAextractionfrommoredelicatespecimens，saysGeigl.Andthatcouldshedmorelightonthestoryofhumanevolution.(640wordsnature)

GlossaryPalaeontologists古生物學家Aurochs歐洲野牛Neanderthal(人類學)尼安德特人，舊石器時代旳古人類。Permafrost(地理)永凍層-Questions1-6AnswerthefollowingquestionsbyusingNOMORETHANTHREEWORDSforeachanswer.1.Howdidpeopletraditionallytreatfossils?2.WhatsuggestionsdoGeiglandhercolleaguesgiveonwhatshouldbedonewhenfossilsarefound?3.Whatproblemsmaybeposediffossilbonesarewashedon-site?NameONE.4.WhatcharacteristicdofossilboneshavetomakethemsusceptibletobecontaminatedwithcontemporaryDNAwhentheyarewashed?5.Whatcouldbebetterunderstoodwhenconservationtreatmentsareimproved?6.Thepassagementionedseveralanimalspeciesstudiedbyresearchers.Howmanyofthemarementioned?Questions7-11Dothefollowingstatementsagreewiththeinformationgiveninthepassage?PleasewriteTRUEifthestatementagreeswiththewriterFALSEifthestatementdoesnotagreewiththewriterNOTGIVENifthereisnoinformationaboutthisinthepassage7.IntheirpaperpublishedintheProceedingsoftheNationalAcademyofSciences，GeiglandhercolleagueshaveshownwhatconservationpracticesshouldbefollowedtopreserveancientDNA.8.ThefossilbonesthatGeiglandhercolleaguesstudiedareallfromthesameaurochs.9.Geneticistsdon‘thavetoworkonsite.10.OnlynewlyexcavatedfossilbonesusingnewconservationmethodssuggestedbyGeiglandhercolleaguescontainancientDNA.11.Paaboisstillworriedaboutthepotentialproblemscausedbytreatmentsoffossilsintraditionalway.Questions12-13CompletethefollowingthestatementsbychoosingletterA-Dforeachanswer.12.“Thisinformation”inparagraph3indicates：[A]ItiscriticaltofollowproperpracticesinpreservingancientDNA.[B]ThebestwayofgettinggoodDNAistohandlefossilswithgloves.[C]Fossilhuntersshouldwearhome-madehammerswhilediggingupbones.[D]Manypalaeontologistsknowhowoneshoulddointreatingfossils.13.ThestudyconductedbyGeiglandhercolleaguessuggests：[A]thefactthatancientDNAcannotberecoveredfromfossilbonesexcavatedinthepast.[B]thecorrelationbetweentheamountofburyingtimeandthatoftherecoveredDNA.[C]thepaceatwhichDNAdegrades.[D]thecorrelationbetweenconservationpracticesanddegradationofDNA.

1.washing，brushing，varnishing見第一段。2.handlingwithgloves/freezingsamples(anyoneofthetwo)見第二段。3.losingauthenticDNA/beingcontaminated/contamination(anyoneofthethree)見第八段“NotonlyistheauthenticDNAgettingwashedout，butcontaminationisgettingwashedin”(答beingcontaminated或contamination比較保險)4.theyareporousporous旳意思是多孔旳。見第八段“……whichcanallowwater—andcontaminantsintheformofcontemporaryDNA—topermeateintotheporousbones.”5.humanevolution見第十五段。其中“shedlightonsth”旳意思是使某事顯得非常清晰，使人理解某事。6.4分別為第四段旳“anextinctcattlespecies，calle